My wife was driving my 00' XJR this evening and I was behind her in our other car. Every time she accelerated (leaving my VW behind), white smoke came out of the driver side tailpipe. It was a short burst of smoke each time and always from the driver side. Does this sound like a valve seal or something worse?

 

Valve seals give out blueish smoke and it mainly happens at engine start up . I hate to bear a bad news but I didn't like the way it came out , white smoke could indicate headgasket or something major

 

What fuel have you been using? and has the car sat for any length of time? I've noticed that condensation within the engine can cause this. As the engine cools, condensation gathers inside it, what you might be seeing is the water being blown off. Another cause can be ethanol in the fuel, some companies use it. Ethanol is hydroscopic and draws water into the tank, this also leads to steam blowing off.
I use Shell V-Power because no ethanol is used in this fuel.

These are alternatives to the head gasket issue - if you are loosing coolant, or oil is present in your header tank where you top up the coolant, it's time to take it to a shop for a "sniff test", this is pretty reliable at confirming if you have a headgasket issue.

 

I was actually wondering about the ethanol theory. There is no coolant loss, no oil in reservoir, and it runs like new. There is a gas staion near by selling ethanol free fuel. I give it a try and see if it clears up.

 

Take it for a 50 mile drive, then see if the problem persists.

If it does not, it is probably just condensation built up in the exhaust system, and one side is a bit different from the other.

If it was an engine fault, in theory, on a XJR with a factory exhaust it should be noticeable on both sides. This is because the front central muffler combines gases from both banks.

 

I noticed that it is coming out of both sides. Only happens under hard acceleration too.

 

I've always thought my XJ8 had a bit more white smoke out of the tailpipes than I'm used to seeing from other cars.

My compression is good and and there is no pressure loss when doing a cooling system pressure test so I am going to chalk this up as a characteristic of the car.

Do the same tests and put your mind at ease.

FWIW, I've put 15,000 miles on my car since I first noticed the "characteristic".

Ken Wolkens

 

If it comes through the tests I agree with Ken.

When it's a hot day, I can't see anything out the back. Once the temp goes down enough for water to condense - white smoke is evident, but how much? If it concerns you why not make a video and post it here so we can assess how much you're talking about.

A cold start with idle videoed.....then let it warm up, a few revs, also on video.

We could compare. I know the engines produce a fair amount of H2O out the back without a head gasket problem, but once up to temp it's eases because of any standing water in the exhaust being gassed off. When you accelerate hard, this is what you could be seeing.

I'm not seeing as much since switching to ethanol free...

 

That's interesting about the ethanol. I googled ethanol-free gasoline and there are a couple of sites with locations, but unfortunately none are within 50 miles of me. It seems that they are usually away from cities. Maybe it's a metropolitan area restriction over here. Oh well. Are we sure we're talking white smoke here and not blue smoke ? White could be condensation, blue could be valve seals, but I haven't seen many posts about the AJ26 or AJ27 engines burning much oil.

 

I'll categorically disagree with the water-in-ethanol story. The fuel systems in cars built from the early 70s onwards are sealed, primarily to contain vapours for emissions purposes, but having the side benefit of not allowing an exchange with outside air with potential moisture.

If there was enough water in contaminated gas to cause a vapour/steam cloud from the tail pipe, it's unlikely the car would start in the first place.

The present 'panic' and myths with E10 gas is amusing to those of us that have been using it for over 20 years without the slightest issue. Much of North America has had it since the 80s or 90s (without knowing about it) but suddenly the sky is falling since the word got out..............

Did Al Gore miss an opportunity?

 

I'll perform the tests this week and try to post a video. The car runs great otherwise. Would a clogged blow-by pipe cause back up?